La Oroya polymetallic smelter had been operated by Doe Run Peru, a unit of the U.S.-based Renco Group, from 1997 until the company went bankrupt in 2009 and its assets were transferred to a group of former creditors.

On the 20th anniversary of the breach of the tailings pond at the Los Frailes mine in Spain, environmental organizations held a press conference to alert the public about the possibility of a similar accident taking place.